In the management of distributed networks that include mobile terminals, the need for proper management and understanding of the remote terminals is an important factor in preventing interference with one another. Thus, systems are continually being developed to identify remote terminals and their location within a general area and also to determine when the remote terminal has passed from one general area to another. The system for air traffic control managed by the Federal Aviation Administration (FAA) is one such system wherein fixed base stations monitor aircraft traffic and provide instruction to the aircraft and to a next station within the aircraft's flight path when the aircraft passes from one area to a next area. A second base station that operates on a different frequency may manage the next area. Thus, the pilot of the aircraft may be instructed to switch to the frequency of the second base station. Or may know, apriori, the frequency of the next station and may switch to it just prior to leaving the coverage area of a first base station.
However, the FAA system is one that is fairly well regulated and controlled by the FAA, as there are a limited number of base stations and remote terminals within a given coverage area. Typically, as most commercial flights are pre-planned, the air traffic handlers and pilots have a general knowledge of the operating conditions of the aircraft and of the base stations. Thus, the aircraft may move effortlessly through different areas without experiencing signal interference with other aircraft. This spoken protocol between the elements of the air traffic control system satisfies the low bandwidth demands on these communication channels. However this protocol is extremely wasteful when implemented for a high bandwidth machine controlled messaging system.
In a national rail communication network, which has developed over a significantly longer time and generally fails to have central authority to manage the network or to control deployment of new equipment. The number of elements within the train network is significantly larger than that of the air traffic control system. In addition, the amount of data to be transferred and the autonomous nature of the transfer of data among the train network elements require more limited human communication to control the network.
For example, a train network system may include a plurality of wayside transmitters/receivers that monitor and/or control the operation of railroad crossing and bridges in addition to a number of base stations that are separated by a finite distance that monitor and control the wayside transmitters/receivers within a designated area. The wayside transmitters/receivers may be in wireless communication with a corresponding base station and the base stations may be in wireless and/or wired communication with each other.
In addition, a plurality of trains, representing fixed or mobile remote terminals, may enter and leave a base station control area and may be detected by one or more wayside stations. The wayside stations may provide information regarding the location of the detected remote terminal to the base station for management. For example, a base station, after receiving information from a first wayside station may anticipate the arrival of the remote terminal within a known distance of a next wayside station and provide information to the next wayside station to control, for example, a crossing gate or a lighting sequence. The next wayside station may further provide information that the remote terminal is approaching or has passed completely through the wayside station.
In order to operate properly, the devices within the network must be synchronized to avoid interference and/or data collisions, as errors in the control of wayside stations may cause significant damage.
However, as new equipment may be deployed in a train system, for example, wherein the new equipment is added to the network without considering whether the new equipment (devices) is compatible with all previously deployed equipment. Thus, it is possible that a device attached to a remote terminal may enter an area in which the device is not compatible with the wayside station and/or the receiving base station regulating the area.
Hence, because of the vast number of channel users and messaging throughput required of the rail application, there is a need for a system that allows for management of communication among different devices in the rail communication system.